The present invention relates generally to data processing systems and more particularly to a new approach to the basic structure, or "architecture" of programmable digital data processing systems.
A programmable digital data processing system can be defined as an assemblage of physical information processing and storage components, "hardward", which are interconnected and operationally under the basic control of an internally stored sequence of instructions, called "software". The same hardware, when provided or "programmed" with different software, can be used to perform a wide range of desired digital data processing tasks of a complex nature. The choice of the particular information processing functions to be performed by each hardware element, the numbers of such elements, and their arrangement into an interconnected structure which provides for data communication between elements in an orderly fashion under the control of a stored sequence of instructions or program, which instructions may be treated as data to be processed or modified by the hardware elements, can be defined as the architecture of such a system.
Three basic architectures known to the prior art are further described in the Detailed Description which follows. These architectures, as is true of most data processing systems of the type usually referred to as "general purpose computers", are such that the cost and degree of complexity of the software needed to program them to achieve a desired set of information processing operations have become inordinately high in many areas of application, such as automation systems, which require complex "real-time" digital data processing functions.